Modern production lines for the manufacture of metal tubing are capable of forming the tubing in essentially continuous lengths. In order to package and transport such tubing, auxiliary cut-off equipment is employed to sever the tubing into standard and/or customized lengths. While improvements have been made in tube cut-off equipment, such equipment nevertheless often produces a constriction or "dimple" in the tube wall adjacent the cut ends, and, in some cases, "burrs" or sharp protruding sections of metal at the cut end. These defects are particularly noticeable in lighter gauge metal tubes which are often used in applications where dimples or burrs are wholly unacceptable such as in the manufacture of childrens' toys, lawn furniture, etc.
Apparatus have been developed for automatically removing dimples from the tube wall at the cut ends of tubes. One type of commercially available dedimpler apparatus includes a pair of conical-shaped dedimpler plugs or tools, one of which is positioned on each side of a tube conveying device. A tube is moved by the tube conveying device to a dedimpler station where the two conical dedimpler plugs are axially moved toward one another, into the opposed open ends of the tube, and then rotated relative to the tube end to restore the tube to a cylindrically true condition. Preferably, a pressure roller is radially aligned with each of the conical dedimpler plugs and positioned in contact with the outer-surface of the tube ends in order to provide support for the tube wall against the dedimpler plugs and prevent flaring of the cut ends.
Dedimpler apparatus of the type described above must be operated so that the opposed dedimpler plugs are axially moved toward and away from the tube ends in timed sequence with one another, and with the movement of the tubes to and from the dedimpler station. Pneumatic or hydraulic cylinders have been used in the past to effect axial movement of the dedimpler plugs, and typically a separate set of cylinders is provided for each dedimpler plug on opposite ends of the tube. Particularly at higher operating speeds, e.g., in excess of about 80 tubes per minute, it has been found to be difficult to precisely synchronize the axial movement of the two dedimpler plugs with one another, and with the movement of the tubes to and from the dedimpler station, using pneumatic or hydraulic cylinders. This limits the speed at which such dedimpler apparatus can be operated without damaging the tubes.
In addition to the dedimpling operation, many tubes require burrs to be removed from their cut ends before such tubes can be used in the manufacture of a product. Automatic deburring devices have been employed for this purpose which generally comprise a pair of brush heads laterally spaced from one another on either side of a tube transfer conveyor. The tube transfer conveyor is effective to simultaneously move a number of tubes atop a side rail carried by each brush head such that the cut ends of each tube move past a deburring brush carried by each brush head.
Deburring apparatus of the type described above must be adjustable to accommodate tubes of different diameter and length. For example, it is necessary to adjust the vertical position of the side rails with respect to the deburring brushes for tubes of varying diameter such that the cut ends of each tube are presented at the proper position relative to the deburring brushes. Adjustment of the vertical position of the side rails in many types of deburring apparatus is time-consuming, and it is difficult to ensure that the side rail on one of the brush heads has been adjusted to the same vertical position as the side rail on the other brush head.
Adjustment of deburring apparatus for tubes of different length has also presented difficulties in the past. The cut ends of the tube must be accurately located with respect to the deburring brushes in each brush head so that such brushes are located close enough to the tube ends to effectively remove burrs therefrom, but not so close as to damage the brushes or tubes. In order to obtain such length adjustment, at least one of the brush heads is movable laterally toward and away from the other brush head which varies the lateral space or width of the tube transfer conveyor therebetween. This tube length adjustment is time-consuming in many deburring apparatus, and may be performed with less than the desired accuracy.
Another problem with many prior art deburring apparatus is an inability to account for wear of the deburring brushes. After a period of use, deburring brushes become worn to some extent and their lateral position relative to the cut ends of the tube must be adjusted to maintain sufficient contact with the tubes to remove burrs. Such lateral adjustment of the deburring brushes, if permitted at all, is a time-consuming operation and it is difficult to adjust the position of the deburring brush in one of the brush heads to the same position as the deburring brush in the other brush head.
In addition to the set-up problems and limited operational speeds described above, it has been found that an inordinate amount of manual intervention is required to complete the dedimpling and deburring of tubing. Dedimpler and deburring apparatus are typically stand-alone units, and often require manual loading of tubes. After a group of tubes are manually loaded and re-sized by a dedimpling apparatus, for example, such tubes must then be retrieved, transported to a stand-alone deburring apparatus, manually fed to such deburring apparatus and then retrieved again after the deburring operation is completed. The multiple, manual operations required to perform both the dedimpling and deburring operations increase costs and reduce productivity.